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Thu, 21 Nov 2024 15:22:29 +0000 (UTC) Received: from dovecot-director2.suse.de ([2a07:de40:b281:106:10:150:64:167]) by imap1.dmz-prg2.suse.org with ESMTPSA id VS5cIDVQP2eaSwAAD6G6ig (envelope-from ); Thu, 21 Nov 2024 15:22:29 +0000 From: Paolo Perego To: linux-staging@lists.linux.dev, linux-kernel@vger.kernel.org Cc: Dave Penkler , Greg Kroah-Hartman , Dan Carpenter , Kees Bakker , Paolo Perego , Arnd Bergmann Subject: [PATCH v2] staging:gpib: Fix a dereference before null check issue Date: Thu, 21 Nov 2024 16:22:21 +0100 Message-ID: <20241121152221.6415-1-pperego@suse.de> X-Mailer: git-send-email 2.47.0 Precedence: bulk X-Mailing-List: linux-staging@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Spam-Level: X-Spamd-Result: default: False [-2.80 / 50.00]; BAYES_HAM(-3.00)[99.99%]; MID_CONTAINS_FROM(1.00)[]; NEURAL_HAM_LONG(-1.00)[-1.000]; R_MISSING_CHARSET(0.50)[]; NEURAL_HAM_SHORT(-0.20)[-1.000]; MIME_GOOD(-0.10)[text/plain]; TO_MATCH_ENVRCPT_ALL(0.00)[]; RCVD_VIA_SMTP_AUTH(0.00)[]; FROM_HAS_DN(0.00)[]; ARC_NA(0.00)[]; MIME_TRACE(0.00)[0:+]; FREEMAIL_CC(0.00)[gmail.com,linuxfoundation.org,linaro.org,ijzerbout.nl,suse.de,arndb.de]; DBL_BLOCKED_OPENRESOLVER(0.00)[imap1.dmz-prg2.suse.org:helo,suse.de:email,suse.de:mid]; RCVD_TLS_ALL(0.00)[]; FROM_EQ_ENVFROM(0.00)[]; RCVD_COUNT_TWO(0.00)[2]; RCPT_COUNT_SEVEN(0.00)[8]; FUZZY_BLOCKED(0.00)[rspamd.com]; TO_DN_SOME(0.00)[]; DKIM_SIGNED(0.00)[suse.de:s=susede2_rsa,suse.de:s=susede2_ed25519]; FREEMAIL_ENVRCPT(0.00)[gmail.com] X-Spam-Score: -2.80 X-Spam-Flag: NO This commit fixes a dereference before null check issue discovered by Coverity (CID 1601566). The check at line 1450 suggests that a_priv can be NULL, however it has been dereferenced before, in the interface_to_usbdev() call. After a discussion, the NULL check is useless because private data is allocated in attach routine and freed in detach routine, so in detach routine the pointer has to be not NULL for sure. Signed-off-by: Paolo Perego Fixes: Removes a useless NULL check --- v2: * After a discussion, we agreed the NULL check is useless because private data is freed in detach routine and allocated while attaching. For such a reason, the pointer has to be not NULL while detaching the device .../gpib/agilent_82357a/agilent_82357a.c | 20 +++++++++---------- 1 file changed, 10 insertions(+), 10 deletions(-) diff --git a/drivers/staging/gpib/agilent_82357a/agilent_82357a.c b/drivers/staging/gpib/agilent_82357a/agilent_82357a.c index bf05fb4a736b..e940429dea19 100644 --- a/drivers/staging/gpib/agilent_82357a/agilent_82357a.c +++ b/drivers/staging/gpib/agilent_82357a/agilent_82357a.c @@ -1447,17 +1447,17 @@ static void agilent_82357a_detach(gpib_board_t *board) a_priv = board->private_data; usb_dev = interface_to_usbdev(a_priv->bus_interface); - if (a_priv) { - if (a_priv->bus_interface) { - agilent_82357a_go_idle(board); - usb_set_intfdata(a_priv->bus_interface, NULL); - } - mutex_lock(&a_priv->control_alloc_lock); - mutex_lock(&a_priv->bulk_alloc_lock); - mutex_lock(&a_priv->interrupt_alloc_lock); - agilent_82357a_cleanup_urbs(a_priv); - agilent_82357a_free_private(a_priv); + + if (a_priv->bus_interface) { + agilent_82357a_go_idle(board); + usb_set_intfdata(a_priv->bus_interface, NULL); } + + mutex_lock(&a_priv->control_alloc_lock); + mutex_lock(&a_priv->bulk_alloc_lock); + mutex_lock(&a_priv->interrupt_alloc_lock); + agilent_82357a_cleanup_urbs(a_priv); + agilent_82357a_free_private(a_priv); dev_info(&usb_dev->dev, "%s: detached\n", __func__); mutex_unlock(&agilent_82357a_hotplug_lock); } -- 2.47.0